Synthesis of 1-Aryl-1 H -indole Derivatives by Iodine-Mediated Cyclization of 2-(Arylamino)styrene Derivatives

A convenient synthetic method for 1-aryl-1H-indole derivatives has been developed. 2-(Arylamino)-α-methylstyrene derivatives were treated with iodine in the presence of sodium hydrogencarbonate to give 1-aryl-3-methyl-1H-indole derivatives in fair to good yields. 3-Ethyl-2-methyl-1-phenyl-1H-indole and 3,3′-dimethyl-1,1′-(p-phenylene)diindole were also prepared from the respective 2-(phenylamino)styrene derivatives under the same conditions in reasonable yields.